SQL Study Notes eight indexes, table join, subquery, ROW_NUMBER

SQL learning notes 8 Indexes, table connections, subqueries, ROW_NUMBER, and SQL Server learning.

SQL learning notes 8 Indexes, table connections, subqueries, ROW_NUMBER, and SQL Server learning.

Index

If you want to query a statement frequently, create an index for it.

Table join

Select T_Oders as o join T_Customers as C on o. CustomerId = c. Id

Subquery

Single-value subquery

Single-Column multi-value subquery


ROW_NUMBER () function

ROW_NUMBER () OVER (order by Fsalary DESC)